Thread protector



Oct. 19, 1954 s. L. PHILLIPS THREAD PROTECTOR Original Filed May 6, 1950 fie. 3

IN V EN TOR. Smzvasr Z. P/mup l I Arron/v5 Y5 Patented Oct. 19, 1954 THREAD PROTECTOR Stanley L. Phillips, Parkview Village, Ohio, as-

signor to Wedge Protectors, Inc., Cleveland, Ohio, a corporation of Ohio Original application May 6, 1950, Serial No.

Divided and this application November 1, 1952, Serial No. 318,261

1 Claim. 1

This invention relates to thread protectors of the kind made from sheet metal and adapted to be applied to the ends of pipes, conduits and machine parts to protect the screw threads of such parts against damage from blows or contamination by foreign matter during handling, shipping and storage.

This application is a division of original application Serial No. 160,495, filed May 6, 1950, now Patent No. 2,627,877.

Thread protectors of this kind are usually discarded as scrap material after a single use and this makes it necessary that the protectors be manufactured as economically as possible. There are, however, certain requisites which must be met in such thread protectors and which have heretofore prevented the manufacturing cost from being reduced below a certain minimum.

One of these requisites is a certain rigidity and strength needed to protect the thread against blows and which has heretofore been obtained by selecting the weight or gauge of sheet metal stock which will provide the required rigidity and strength in the protectors made from such sheet metal stock. Another such requisite is that the protector have a realtively smooth and finished shape which is devoid of burrs and sharp edges, such that the protectors and the pipes or machine parts to which they are applied, can be handled safely and without danger of causing personal injury or torn clothing. To provide the protectors with such a smooth and finished shape has heretofore required additional forming and trimming operations which have materially increased the cost of manufacture.

The present invention deals successfully with these problems and provides a novel construction for a sheet metal thread protector which will permit the protector to be manufactured more economically and yet without sacrifice in its strength and rigidity or in the smoothness and regularity of its shape.

Another object of this invention is to provide a novel construction for a thread protector of the sheet metal type, in which a hollow annular rim integrally formed on the outer end of the sheet metal sleeve of the protector provides an annular seat for engagement with the end of the threaded member and also reinforces and stiffens the protector so effectively that it can be manufactured from a lighter gauge of sheet metal without any material sacrifice in rigidity or strength.

A further object is to provide an improved thread protector of the character mentioned in which the hollow annular rim is of a radial width such that the periphery thereof extends beyond the periphery of the threaded member and which rim periphery has knurling extending therearound to facilitate obtaining a secure grip on the protector for applying the same to the threaded member but more particularly for removing the protector from such threaded member.

Still another object is to provide an improved thread protector of this character in which a packing is connected with the protector by having a holding portion retained in the hollow annular rim and such packing is adapted for sealing engagement with the end of the threaded member to which the protector is applied.

Other objects and advantages will be apparent in the following detailed description and in the accompanying sheet of drawings in which,

Fig. 1 is anelevation, with portions in longitudinal section, showing one form of the improved thread protector of the present invention applied to an externally threaded pipe end;

Fig. 2 is an outer end view of the thread protector of Fig. 1 showing the same in detached relation; and

Fig. 3 is an elevation, with portions in longitudinal section, showing a thread protector similar to that of Fig. 1 but which includes a packing element.

In the embodiment of the invention illustrated in Fig. 1, a thread protector H) of the outside type is shown applied to a threaded member, in this instance a pipe end H, having an external screw thread !2 thereon.

The thread protector i0 comprises a sleeve l3 which has been drawn or otherwise suitably formed from sheet metal and which extends in surrounding coaxial or telescoping relation on the pipe end it so as to cover and protect the screw thread i2 thereof. The thread protector 10 also includes a holding means carried by the sleeve i3 and engageable with the thread I2 for retaining the protector on the pipe end H. In this instance, the holding means is an internal helical thread 14 formed on the intermediate portion only of the sleeve I3. The thread I4 comprises a number of continuously connected thread convolutions such as can be formed by a rolling or swaging operation during which metal of the Wall of the sleeve I3 is deflected substantially radially inwardly and formed into substantially V-shaped thread ridges.

The thread protector I0 is applied to the pipe end H and is removed therefrom by a rotary movement during which the protector is screwed onto or off of the pipe end. The protector It is constructed so that it preferably has an axial length somewhat longer than the threaded portion of the pipe and such that when the protector is fully applied it will cover and shield the threaded portion against blows which would be damaging to the thread and against foreign matter of all kinds which might contaminate or corrode the thread.

As an important feature of the present invention the thread protector I is provided at its outer end with a hollow annular bead or rim I which is integrally connected with the sleeve I3 and is substantially radially inwardly offset therefrom so as to occupy a position in an inwardly overhanging relation such that it will engage the annular end face I6 of the pipe end I I when the protector is screwed onto the thread I2. The hollow annular rim I5 is formed by the sheet metal of the outer end of the sleeve I3, such sheet metal being deflected so as to extend in an inwardly ofiset and reversely curled relation as shown in Fig. 1 of the drawing. Such deflection of the sheet metal of the outer end of the sleeve l3 into this reversely curled relation to define the hollow annular rim I5 can be accomplished by any suitable drawing, forming or spinning dies by which sheet metal operations of this kind are accomplished.

The hollow annular rim I5 is defined by integral wall portions of the sheet metal sleeve I3 which include a substantially radially inwardly extending annular wall portion I5 an axially extending annular wall portion I5 and a substantially radially outwardly extending annular wall portion I5. These annular Wall portions I5, I5 and I5 are integrally connected continuous portions of the sheet metal located at the outer end of the sleeve I3 and define the above-mentioned inwardly deflected and reversely curled portion of the sleeve which defines the annular bead I5. As shown in Fig. 1, the outwardly extending annular portion I 5 approaches, but preferably does not engage, the wall defining the main portion of the sleeve I3.

When the thread protector I0 is applied to the pipe end II, the inwardly offset hollow annular rim I5 engages the end face It of the pipe end and, in cooperation with the thread I4, produces wedged or locked engagement on the pipe end for retaining the protector thereon. The hollow annular rim I5, and particularly the outwardly deflected annular portion I5 thereof, will be capable of some springing or yielding when the protector is applied to the pipe end for producing this locked effect and also as the result of blows delivered against the outer end portion of the protector during handling or shipping of the pipe. Since the annular rim I5 is hollow and has this limited yielding or spring characteristic, it will readily absorb such blows or jars and prevent the same from damaging the threaded end of the pipe.

As another feature of this invention the improved thread protector III is constructed so that the hollow annular rim I5 will have an axial width such as to locate the inner periphery of the rim at a point inwardly of the inner surface or periphery I! of the pipe and this inner periphery of the rim is provided with knurling I8. When the hollow annular rim I5 has such an increased radial width and carries the knurling 18 on its inner p ph ry, an appr pri tool or a secure handgrip can be applied to the protector 4 for more easily unscrewing the same from the threaded pipe end II when the protector is to be removed.

One important advantage resulting from the above described construction for the thread protector I0 is that the hollow annular rim I5 reinforces and stiifens the sheet metal sleeve I3 to such an extent that the protector Ill can be made from a much lighter gauge of sheet metal stock than has heretofore been practical. For example, it is pointed out that when the thread protector I0 is of a size to be applied to a pipe of approximately 2% inch normal size, it was necessary heretofore to make the protector out of sheet metal stock of 13 gauge. With the improved construction here shown for the protector I9, the increased rigidity afforded by the hollow annular rim I5 makes it possible to construct the protector out of sheet metal stock of 16 gauge, or even a lighter gauge, without materially sacrificing any strength or rigidity in the protector. The lighter gauge of sheet metal stock now used can be more easily formed than the heavier gauge heretofore used and therefore results in an advantage in die expense, both as to initial die cost and die maintenance.

Another important advantage resulting from the hollow annular rim I5 is a manufacturing advantage in that a protector of a smooth and regular shape and devoid of dangerous burrs and sharp corners can be made with fewer manufacturing operations. This is possible because during the manufacture of the thread protector Iii the sheet metal at the outer end of the sleeve I3 can usually be formed to its inwardly deflected and reversely curled condition during a single forming operation and, since the extreme annular end of the sleeve I3 is disposed in the finished protector in a position where it will not be engaged by the hands or clothing of the workmen handling the protector or the pipe carrying the same, it will not require any trimming or smoothing operation as has heretofore been necessary to remove or eliminate such dangerous burrs and sharp edges.

Fig. 3 of the drawing shows a thread protector 20 of a construction generally similar to the above described thread protector I0 and applied to the external thread 2I of the pipe end 22. The thread protector 28 comprises a sheet metal sleeve 23 carrying an internal thread 24, as above explained, for retaining the protector on the pipe end 22. The protector 25 also includes a radially inwardly offset hollow annular bead or rim 25 which is formed by the sheet metal of the outer end of the sleeve 23. As in the case of the hollow annular rim I5 described above, the rim 25 is formed by inwardly, axially and outwardly extending continuously connected annular portions 25*, 25 and 25 which constitute the inwardly and reversely curled end portion of the sleeve 23.

The thread protector of Fig. 3 embodies the additional feature of a packing 26 carried by the outer end of the protector 2,5 and engageable with the outer end of the pipe 22 when the protector is applied thereto. The packing 26 has a holding portion 21 which is locked or retained in the annular recess 28 of the hollow rim 25 and also includes a ring portion 29 projecting from the hollow rim and adapted for sealing engagement w th th x rem end po i o t ip 2 or the initial thread convolution 2P thereof.

The p ki 6 may be a ring f rm d o y material suita le for s aling purp es tw n the protector and the pipe end such as paper, asbestos or other fibrous material, rubber or rubber-like material, or a soft metal such as brass, copper, or aluminum. This packing ring can be assembled into connected relation with the protector 20 without requiring any additional manufacturing operation, by simply placing the packing ring in a position to have the holding portion 27 thereof engaged and confined in the recess 28 of the hollow rim 25 when the sheet metal of the outer end of the sleeve 23 is deflected into the above described reversely curled relation. Such deflection of this portion of the sleeve 23 causes the annular portion 25 to engage the packing ring 26 and press the same against the main wall of the sleeve 23 with the relatively enlarged retaining portion 21 confined or locked in the recess 28.

When the protector 20 has been applied to the pipe end 22 the packing 26 will assist in causing the protector to be securely held on the pipe and will also assist in centering the outer end of the protector on the pipe end. This packing will also serve the purpose of absorbing some of the blows and shocks which are delivered against the outer end of the protector during handling and shipping of the pipe and will form a seal at the outer end of the pipe which will assist in excluding foreign matter which might otherwise corrode or contaminate the thread 2 I.

From the accompanying drawing and foregoing detailed description it will now be understood that this invention provides an improved construction for a thread protector to be used on the threaded end of a pipe, machine part or other member and which protector can be more economically produced because the integral hollow annular rim formed on the outer end of the protector stifiens and reinforces the same so that a lighter gauge of sheet metal can be used. It will also be seen that this hollow annular rim has a springing and yielding action for absorbing blows which high otherwise damage the threaded end of the member and this rim of itself, or assisted by a packing member, also forms a seal with the outer end of the member to which the protector is applied and accomplishes a locking cooperation with such outer end by which the protector is held against accidental unscrewing. Additionally, it will be seen that in the improved protector the hollow annular rim is of a radial width and carries knurling such that the peripheral edge thereof will extend beyond the periphery of the member to which the protector is applied and will facilitate the application or removal of the protector by the use of a suitable tool or a handgrip. It will be seen, furthermore, that the use of the hollow annular rim at the outer end of the protector not only produces a stronger and more rigid protector from a lighter gauge of sheet metal, but the radially deflected and reversely curled relation of the sheet metal of the outer end of the sleeve which forms this hollow annular rim eliminates the need for trimming the sheet metal, or performing other machine operations thereon at this point which have heretofore been necessary to remove dangerous burrs and sharp edges.

Although the improved thread protector of the present invention has been illustrated and described herein to a somewhat detailed extent it will be understood, of course, that the invention is not to be regarded as being limited correspondingly in scope but includes all changes and modiflcations coming within the spirit of the invention and the language of the claim hereof.

Having thus described my invention, I claim:

A thread protector for application to a cylindrical member having a helical thread on the outside thereof comprising, a one-piece sheet metal sleeve, a group of thread elements formed on an intermediate portion of the Wall of said sleeve and engageable with said helical thread for retaining the protector in connected relation with said member, the sheet metal of the outer end of said sleeve being deflected so as to define a radially oflset hollow annular rim thereon formed by continuously connected annular wall portions consisting of axially spaced first and second substantially radially extending flange portions and an axially extending portion connecting said second flange portion with said first flange portion, said hollow annular rim forming a stiiTening means and an internal annular end seat on the outer end of said sleeve, the portions of said sleeve on opposite sides of said group of thread elements being plain cylindrical portions of a diameter to have a spaced relation to said helical thread When the protector is applied to said member, said first flange portion forming an end wall on said protector at the outer end thereof and said second flange portion forming said internal annular end seat in said protector for seating engagement with the end face of said member and said second flange portion terminating in a free annular edge presented toward the main wall of said sleeve at a point between said first flange portion and said thread elements, said free annular edge being spaced from the main wall of said sleeve by an intervening annular slot, and a packing retained in said hollow annular rim and having an annular portion projecting from said rim through said annular slot for continuous annular sealing engagement with the end of said member.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 676,976 Bossert June 25, 1901 686,128 Proudfit Nov. 5, 1901 689,278 Bossert Dec. 17, 1901 1,584,313 Mallory May 11, 1926 2,195,530 Curtis Apr. 2, 1940 2,215,251 Prince Sept. 1'7. 1940 

